Master cam actuator



H. E. BALSIGER 3,271,905 MASTER CAM ACTUATOR 3 Sheets-Sheet 2 Sept. 13, 1966 Filed Dec. 20, 1963 I III Q QM. um Q G k m 3 Q m 3 s INVENTOR HAROLD 5.2.41.5/651? ATTORNEY P 1966 H. E. BALSIGER 3,271,905

MASTER CAM ACTUATOR Filed Dec. 20, 1963 3 Sheets-Sheet 3 INVENTOR HAROLD E.BALS/GER ATTORNEY United States Patent 3,271,905 MASTER CAM ACTUATOR Harold E. Balsiger, Waynesboro, Pa, assignor to Landis Tool Company, Waynesboro, Pa. Filed Dec. 20, 1963, Ser. No. 332,084 9 (Ilaims. (Cl. 51-101) This invention relates to grinding machines, particularly machines for grinding automotive camshafts having axial-1y spaced cam portions to be ground.

In the grinding of automotive camshafts, the contour of each cam is determined by a corresponding master cam on a master camshaft mounted for rotation with the camshaft and gene-rally in axial alignment with said camshaft. The master cam and camshaft are rotatably supported on a cradle which, in turn, is mounted on the work table of the machine. The master cam is rotated in engagement with a follower roller so that the cradle is rocked in accordance with the contour of the master cam. The master cam is held in engagement with the master cam follower by means of a spring or equivalent device.

During a rough grinding operation, the feeding pressure of the grinding wheel distorts the workpiece and work support and tends to separate the master cam and follower. These distortions result in inaccuracy in form and size of the workpiece. In order to minimize such distortions, the spring used to hold the master cam against the follower must be strong enough to resist the tendency to separation. However, when the rough grinding feeding pressure is reduced to finish grinding pressure, such a spring produces variable distortions of the cradle and workpiece depending on the axial position of the follower roller. Since the follower roller serves as a sort of pivot, the direction of distortion effected by the spring force varies with the axial position of the follower rol-ler. When the follower is in the position shown, the spring tends to distort the workpiece and cradle in a clockwise direction. When the follower is at the other end of the master cam, the spring tends to distort the cradle and workpiece in a counter-clockwise direction.

In the past, the rough grinding operation was performed on one machine with a heavy spring to resist the distortion caused by the rough grinding feed. The finish grinding operation was performed on a machine in which the spring was arranged to exert a lesser force on the cradle in accordance with the lesser feeding force of the finish grinding operation.

It is, therefore, desirable to change the force holding the master cam against the roller for rough grinding to a force more in accordance with the lighter grinding pressure on the work during a finish grinding operation and thus perform rough and finish grinding in one ope-ration on one machine.

It is, therefore, an object of the present invention to provide means whereby a rough and finish grinding operation may be performed on a camshaft in one machine.

Another object is to provide means to apply one force to hold the master cam and follower in engagement during the rough grinding operation and to change this force automatically for the finish grinding operation.

Another object is to provide means operable at a predetermined point in a grinding cycle to change the force which holds the master cam and follower in contact.

FIG. 1 is a plan view of a cam grinding machine.

FIG. 2 is a partial sectional end elevation on the line 22 of FIG. 1, showing an alternate device for changing the spring pressure which holds the master cam in engagement with the follower roller.

FIG. 3 is also a partial sectional end elevation on line 22 of FIG. 1, showing means for moving the master 3,271,965 Patented Sept. 13, 1966 cam into and out of contact with the follower roller, and also the means for holding the master cam against the follower roller during a grinding operation.

FIG. 4 is a hydraulic and electric diagram.

Details of structure and operation similar to those used in this invention, but not shown and described in the specification, may be found in US. Patent 1,993,854, granted March 12, 1935, and US. Patent 2,243,410, granted May 27, 1941.

Numeral 10 indicates the bed of a grinding machine. Grinding wheel support 11 is mounted on bed 10. Grinding wheel 12 is rotatably mounted on wheel support 11. Work-piece W is rotatably supported between the centers of footstock 15 and headstock 16. Footstock 15, work drive spindle 17, and master cam 18 in headstock 16, are mounted on cradle 20 for rocking movement toward and from grinding wheel 12.

Cradle 20 is supported for rocking movement by support members 21 on work table 22. Work table 22 is, in turn, supported on carriage 2 3 which, as shown in said prior patents, is moved longitudinally or axially to place successive cams on the camshaft in position to be ground by grinding wheel 12.

Follower roller 30 is rotatably and slidably mounted on shaft 31 on which it moves axially in timed relation with carriage 23 to engage successive master cams corresponding to the cams to be ground on workpiece W.

Master cam 18 and workpiece W are rotated by motor 40 to which work drive spindle 17 is attached by suitable driving connections (not shown). The means for mov ing master cam 18 into and out of engagement with follower ro-ller 30 consists of a piston 50 in cylinder 51 in headstock 16. Piston 50 is connected through piston rod 52 to sleeve 53 slidably mounted in bore 54 in headstock 1 6. Sleeve 53 contains a spring 60, one end of which bears against flange 61 on abutment 6-2. Flange 61 is threaded into sleeve 53 for axial adjustment therein in order to adjust the load on spring 60. The other end of spring engages washer 65. Rod 66 having a rounded head 67 in engagement with end portion 75 of arm 70, extends through washer and spring 60. End portion 7 1 of rod 66 is reduced in diameter and has a spherical end portion 72 which slides in bore 68 in abutment 62. Arm 70 attached to cradle 20 has an end portion 7-5 extending through an opening 73 in sleeve 53. End portion 75 has a recess 76 for receiving head 67 of rod 66.-

Spring 60 is loaded by adjusting abutment 62 so that it will hold master cam 18 against follower roller 30 with a force suitable for finish grinding.

For rough grinding, the force to hold master cam 18 in engagement with follower roller 30 is applied by spring 80 which acts through member 81 to engage end portion 75 of arm 70. The other end of spring 80 is held in contact with abutment 82 slidably mounted in cylinder 83 in headstock 16. Bar 85 is pivot-ally attached at one end to abutment 82. Pin in member 81 protrudes into a longitudinal slot 91 in bar 85. Spring 80 is loaded by piston 97 in cylinder 95 through piston rod 96 attached to abutment 82.

During a rough grinding operation, spring 80 is loaded by advancing piston 97 to the right to exert a greater force on cradle 20 than that exerted by spring 60. At the end of the rough grinding operation, piston 97 is retracted to the left, leaving only spring 60 to hold master cam 18 and follower roller 30 in engagement for the finish grinding operation.

In the alternate arrangement in FIG. 2, abutment 62 is slidably mounted in sleeve 53 and is moved axially to change the load on spring 60 by means of a piston (not shown) in cylinder 101. Cylinder 101 is attached to headstock 16. Piston rod 102 is threaded into end portion 69 of abutment 62. During a rough grinding operation, the piston in cylinder 101 is actuated to apply a load to spring 60 suitable for a rough grinding operation. At the end of the rough grinding operation, said piston is retracted to reduce the load on spring 60 so that the force exerted by spring 60 on cradle 20 and master cam 18 is suitable for a finish grinding operation.

Operation At the beginning of a grinding operation, limit switch SLS is closed to complete a circuit to energize relay 7CR.

Relay contact 7CR1 completes a circuit to energize solenoid S which shifts valve 120 to the right, directing fluid under pressure from pump 121 to the rod end of cylinder 51.

Piston 50 in cylinder 51 advances to move master cam 18 into engagement with follower roller 30.

Fluid is also directed by valve 120 to the head end of grinding feed cylinder 130. Piston 131 actuates rack 132 and pinion 133 through suitable driving means to rotate feed hand wheel 135.

Rotation of hand wheel 135 by piston 131 acts through gearing (not shown) to advance wheel support 11 and grinding wheel 12 for a grinding operation. Details of the control means for advancing the grinding wheel at a fast rate for rough grinding and at a slower rate for finish grinding, are described in U.S. Patent 2,899,778, granted August 18, 1959.

At the same time, fluid from pump 121 is directed by valve 140 to the head end of cylinder 95. Valve 140 is held in right hand position by solenoid 6.

. Solenoid 6 is energized through relay contact 11CR1, relay 11CR having been energized through normally closed relay contact 9CR1.

Valve 140 is held in right hand position to advance piston 97 and piston rod 96 to advance spring 80 and pin 90 into engagement with end portion 75 of arm 70.

At the end of the rough grinding operation, cam 136 on hand wheel 135 actuates limit switch 6LS to complete a circuit to energize relay 9CR.

Relay contact 9CR1 opens, deenergizing relay 11CR and opening relay contact 11CR1 to deenergize solenoid 6.

. Valve 140 is returned to the left hand position by spring 141 to direct fluid to the rod end of cylinder 95 and retract spring 80, leaving spring 60 to hold master earn 18 and follower roller 30 in engagement for a finish grinding operation.

For the purpose of illustration, the invention has been shown as functioning at the point in the grinding cycle at which it is generally used, that is, prior to the finish grinding operation. However, the invention contemplates means for either increasing or decreasing the force applied to the master cam at any point in the grinding cycle at which such a change would produce a useful result.

I claim:

1. In a cam grinding machine,

(a) a work carriage,

(b) a cradle pivotally supported on said carriage for rocking movement toward and from a grinding wheel,

7 (c) a master cam rotatably supported on said cradle,

(d) a follower for said master cam,

. (e) holding means for applying a predetermined force for holding said follower and said master cam in contact,

(f) and means operable automatically to change the force exerted by said holding means during a grinding operation.

2. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(c) a feed mechanism for moving said wheel support toward and from said work support,

((1) a cradle pivotally supported on said work support for rocking movement toward and from a grinding wheel,

(e) a master cam rotatably supported on said cradle,

(f) a follower for said master cam,

(g) power means operable through a resilient means for moving said master cam into and out of engagement with said following including (h) a lower pressure spring and a high pressure spring,

(i) and means actuated by said feed mechanism for retracting said high pressure spring.

3. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(c) a feed mechanism for moving said wheel support toward and from said work support,

(d) a cradle pivotally supported on said work support for rocking movement toward and from a grinding wheel,

(e) a master cam rotatably supported on said cradle,

(f) a follower for said master cam,

(g) power means for maintaining contact between said master cam and said follower including (h) high pressure means and low pressure means,

(i) and means actuated in timed relation with the movement of said wheel support toward said work support for rendering said high pressure means inoperative.

4. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(0) a feed mechanism for moving said wheel support toward and from said work support,

(d) a cradle pivotally supported on said work support for rocking movement toward and from a grinding wheel,

(e) a master cam rotatably supported on said cradle,

(f) a follower for said master cam,

(g) power means operable through a resilient means for moving said master cam into and out of engagement with said follower including (h) a lower pressure spring and a high pressure spring,

(i) and means actuated in timed relation with movement of said wheel support toward said work support for retracting said high pressure spring.

5. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(c) a feed mechanism for moving said wheel support toward and from said work support,

((1) a cradle pivotally supported for rocking movement toward and from a grinding wheel,

(e) a master cam rotatably supported on said cradle,

(f) a follower for said master cam,

(g) resilient means for applying a predetermined force for holding said follower and said master cam in contact,

(h) and means operable before the end of a grinding operation for changing the force exerted on said master cam by said resilient means.

6. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(c) a grinding wheel rotatably mounted on said wheel support,

(d) a feed mechanism for moving said wheel support toward and from said work support,

(e) a cradle pivotally supported on said work support for rocking movement toward and from said grinding wheel,

(f) a master cam rotatably supported on said cradle,

(g) a follower for said master cam,

(h) said feed mechanism being operable at a rate to advance said grinding wheel against a workpiece with a predetermined force for rough grinding and at a slower rate to advance said grinding wheel against the workpiece with a lesser force for finish grinding,

(i) means for applying a predetermined force on the workpiece in opposition to the force of said rough g nding feed rate,

(j) and means operable by said feed mechanism to change said opposing force during a grinding operation.

7. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(c) a grinding wheel rotatably mounted on said wheel support,

(d) a feed mechanism for moving said Wheel support toward and from said work support,

(e) a cradle pivotally supported on said work support for rocking movement toward and from said grinding wheel,

(1?) a master cam rotatably supported on said cradle,

(g) -a follower for said master cam,

(h) said feed mechanism being operable at a rate to advance said grinding Wheel against a workpiece wit-h a predetermined force for rough grinding at a slower rate to advance said grinding wheel against the workpiece with a lesser force for finish grinding,

(i) means for applying a predetermined force on the workpiece in opposition to the force of said rough grinding feed rate,

(j) and means operable in timed relation with the movement of said wheel support to change said opposing force for a finish grinding operation.

8. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(c) a feed mechanism for moving said wheel support toward and from said Work support,

(d) a cradle pivotally supported for rocking movement toward and from a grinding wheel,

(e) a master cam rotatably supported on said cradle,

(f) a follower for said master cam,

g) resilient means for holding said follower and said master cam in contact with a predetermined force, (h) and means actuated by said feed mechanism for changing the force exerted on said master cam by said resilient means during a grinding operation.

9. In a cam grinding machine,

(a) a work support,

(b) a grinding wheel support,

(c) a feed mechanism for moving said wheel support toward and from said Work support,

(d) a cradle pivotally supported for rocking movement toward and from a grinding wheel,

(e) a master cam rotatably supported on said cradle,

(f) a follower for said master cam,

(g) resilient means for holding said fol-lower and said master cam in contact,

(h) and means operable at a predetermined point in a grinding operation for reducing the force exerted on said master team by said resilient means.

References Cited by the Examiner UNITED STATES PATENTS 1,914,561 6/1933 Fraser 51-101 1,993,854 3/1935 Ott 51-101 2,243,410 5/1941 Balsiger et a1. 51-101 2,732,668 1/1956 Olsson 51101 LESTER M. SWINGLE, Primary Examiner. 

1. IN A CAM GRINDING MACHINE, (A) A WORK CARRIAGE, (B) A CRADLE PIVOTALLY SUPPORTED ON SAID CARRIAGE FOR ROCKING MOVEMENT TOWARD AND FROM A GRINDING WHEEL, (C) A MASTER CAM ROTATABLY SUPPORTED ON SAID CRADLE, (D) A FOLLOWER FOR SAID MASTER CAM, (E) HOLDING MEANS FOR APPLYING A PREDETERMINED FORCE FOR HOLDING SAID FOLLOWER AND SAID MASTER CAM IN CONTACT, 